Apparatus for making paper or paper board or similar fibrous product



April 14, 1959 R. J. THOMAS APPARATUS FOR MAKING PAPER OR P :APER BOARDs PRODUCT OR SIMILAR FIBROU 2 Sheets-Sheet 1 Filed June 10, 1957nws/vro/a /NALD 75 455 Tum ms,

ATTORNEY April 14, 1959 'R. J. THOMAS 2,381,671

APPARATUS FOR MAKING PAPER 0R PAPER BOARD 0R SIMILAR FIBROUS PRODUCTFiled June 10, 1957 2 Sheets-Sheet 2 INVENTOR PEG/p/flL 0v in/5s Wan/5'ATTORNEY Y United States Patent APPARATUS FOR MAKING PAPER OR PAPERBOARD OR SIMILAR FIBROUS PRODUCT Reginald James Thomas,Weston-Super-Mare, England, assignor to St. Annes Board Mill CompanyLimited, Bristol, England, a British company Application June 10, 1957,Serial No. 664,808 Claims priority, application Great Britain June 12,1956 4 Claims. (CI. 9239) This invention relates to apparatus for makingpaper or paper board or similar fibrous product from watery pulpdelivered to a travelling carrier band, or to formed pulp carried bysaid band, said apparatus being of the kind comprising a permeablemember adapted to be arranged above the band to move therewith forsqueezing the unformed pulp against the band to assist in separatingwater therefrom, and means for removing separated water which flowsthrough said member.

The squeezing of the watery pulp by the apparatus above referred tobrings about a restriction in the free flow of the watery pulp on thecarrier band, or formed pulp, and so results in the build up of aturbulent pond or pool of pulp extending rearwardly from the positionwhere the squeezing action commences, the rearward extent of said ponddepending on the speed of movement of the carrier band.

The turbulence of the pond causes agitation of the solid content of thepulp and so tends to orient the fibres in all directions and at the sametime flows them towards the permeable member whereby the water passestherethrough so as to form or felt the pulp on said member.

The present invention particularly relates to apparatus of the abovegeneral kind in which the permeable member in co-operation with the bandis arranged to provide a tapering gap into which the watery pulp iscarried and that constitutes a restriction in the free flow of the pulp.

In such apparatus, the aforesaid turbulent pond extends from the forwardend of the wedge shaped gap rearwardly and the distance it'extendsrearwardly depends on the speed of the carrier band.

For example, if the band is running fast, then the pond may only be aninch or even less in length rearwardly and in this case formation startsto take place on the permeable member for a substantially similarlength. If, however, the carrier band is running say, at 200 feet perminute or less, then the pond may extend rearwardly for two or threefeet, and then formation will start to take place on a considerablygreater length of the permeable member. It will be appreciated that ifthe pond is short in extent, it is similarly small in height, but if thepond is long then its height is greater so that the pulp flows towardsthe permeable member throughout a greater length.

- The object of the present invention is to provide im proved apparatusfor restricting the flow of watery pulp on a travelling carrier band andthus building up a turbulent pond thereof.

According to a feature of the present invention a permeable surfaceadapted to co-operate with a travelling carrier band to providetherewith a tapering gap that constitutes a restriction in the free flowof the watery pulp, passes around a permeable roller arranged adjacentsaid carrier band, whereby a portion of the periphery, of the roller inco-operation with the band constitutes the tapering gap in which aturbulent pond of pulp may build up and thereby form on saidpermeablemember.

Preferably the roller around which the permeable member passes is oflarge diameter so that in cooperation with the carrier band, it providesa reasonable sized forming area for the turbulent pond of pulp.

Preferably, also, the permeable member comprises an endless wire bandhaving a lower run arranged adjacent the carrier band.

If desired, a sloping chute may be arranged across the upper surface ofthe lower run of the endless wire band beyond the roller whereby waterpassing through said lower run, due to its momentum, flows up said chuteto a channel and is removed.

Alternatively or in addition, a suction box, or suction chute, may bearranged across the upper surface of said lower run beyond the largediameter roller whereby water passing through said run may be drawn upinto said box or chute and removed.

The roller may include a suction member adapted to draw water throughthe perforations.

The roller may be of cellular construction, that is to say its surfacemay comprise a plurality of transverse and peripheral strips whereby anumber of polygonal cells are provided.

If desired the transverse strips may be arranged at an angle to theradius of the roller, whereby they act, due to rotation of the roller,to pick up water passing into the cells, and fling it towards the chute.

Forms of apparatus in accordance with the present invention will now bedescribed with reference to the accompanying drawings in which:

Fig. 1 is an elevation showing apparatus for dewatering a single layerof pulp; this may constitute the first dewatering device in a multi-plymachine.

Fig. 2 is a fragmentary end view to a larger scale than Fig. 1 of oneform of roller for providing the upper surface of the tapering gap.

Fig. 3 is a view taken from the left-hand side of Fig. 2, showing partof a wire cloth covering thereon removed.

Figs. 4 and 5 are views similar to Figs. 2 and 3, illustratingmodifications.

Figs. 6 and 7 are also views similar to Figs. 2 and 3 illustratinganother construction of roller.

Fig. 8 is a view corresponding to Fig. 1 but showing modifications tothe apparatus.

The apparatus comprises legs 1 secured to the ground carrying uprights 2adapted to support an overhead framework 3.

A breast roll 4 is rotatably mounted on the legs 1 and a main travellingcarrier band 5 is trained around said breast roller 4, and other rollersnot shown, so as to provide a substantially horizontal upper run 6. 7and 8 are support rollers for said upper run 6.

The upper framework 3 carries by means of rotatable bearings a permeablemember in the form of an endless wire band 9, whose lower stretch 10runs substantially parallel with the said upper run 6. Thus saidpermeable member 9 is trained around rollers 11 to 17, the latter beingperforated. The roller 17 functions as an oncoming directing rollpositioned so that it presses the lower stretch 10 of the upperpermeable wire 9 down against the upper stretch 6 of the carrier band 5.By this means the quadrant of the roller from the 6 oclock position tothe 9 oclock position lies above the stretch 6, and the tapering gap inwhich formation starts to take place is provided by the periphery of theroller 17 contained within said quadrant in co-operation with theportion of the upper stretch 6 that it overlies.

As will be seen in the drawing, the roller 17'is of comparatively largediameter so as to provide a reasonable sized forming area (tapering gap)in co-operation with the upper stretch 6. A sloping chute or waterwaysuch as 19 is arranged beyond the perforated roller so that, inoperation, water passing through the periphery of the roller flows upthe slice into the channel 20.

The above described apparatus is suitable for manufacturing a single-plyboard and works in the following manner.

A layer of watery pulp is fed from a head box 21' on to the carrier band6 whereupon it is carried into the above described tapering gapindicated by the numeral 22. At the position where the upper wire isnipped against the band 6 (i.e. 6 oclock) the free flow of the pulp isrestricted so that it builds up as a turbulent pond 23 in the taperinggap 22. This turbulence agitates the solid content in the pulp andorients the fibres in all directions, and flows them towards the upperwire. Water from the pond 23 passes through the upper wire through theperforations in the roller 17, up the slice 19 into the.

channel 20, and the fibres in the pulp start to form or felt on saidwire. downwardly and hence formation also takes place on the carrierband 6.

As the pulp passes clear of the converging end of the tapering gap 22,due to the lower stretch and the upper stretch 6 being squeezedtogether, water continues to pass upwardly through said stretch 10 andthis water also flows up the slice 19 into the channel 24) for removal.

It is thought that in a high speed machine water that passes through thepermeable member is held in the perforations of the roller and issubsequently flung clear of said roller after it has turned past thenip, i.e. the narrow end of the wedge shaped gap.

Instead of using a perforated roller, a cellular roller may be used andone form thereof is illustrated in Figs. 2 and 3. This consists of animperforate drum 24 having transverse and peripheral strips, 25A, 253respectively, say, an inch or two in depth radially, the strips beingarranged about two inches apart both transversely and peripherally so asto provide a roller whose periphery comprises a number of rectangularcells 26 about 2" x 2" square by 2" deep. The periphery of the roller ispreferably covered with a wire covering 27, as shown. In this case waterpassing through the permeable Wire flows into the cells and is carriedthereby beyond the nip (6 oclock position) whereupon it is flungcentrifugally towards the waterway 19. In order to enhance the carryingand flinging eifect of the cells, the transverse strips 25A may bearranged at an angle to the radius of the roller so that the cellsact'to scoop the water passing through the wire and fling it towards thewaterway 19. This angular arrangement of the transverse strips is shownin Figs. 4 and 5; the latter also shows another variation in which theperipheral strips 258 are replaced by a continuous spiral strip 25C.

In a still further form illustrated in Figs. 6 and 7 a wire covering isshown wound around a perforate drum 34, said covering comprising stripsset edge-on in slotted transverse ribs 36. If desired the roller 17 maycomprise a skeleton structure, i.e. a drum having circular ends withtransverse bars joining them together, this skeleton roller may have awire or similar cloth covering. This skeleton type of roller is notillustrated in the drawings.

In using the above described apparatus for dewatering a second orsubsequent layer of pulp i.e. a layer of pulp delivered on to a layeralready formed carried by a travelling band, the operation is similarexcept that the pond 23 may be of larger dimensions since nearly all thewater from the second or subsequent layer will constitute the pond, onlya small quantity being absorbed by the underlying formed layer. Thus itmay be advantageous to provide a larger roller 17 for saidsecond orsubsequent layer inorder to provide alarger area inwhichforrnation maystart ,(taperinggap).

Modifications ofthe invention particularly useful in operation oneslowerrunning machine, eg 200 ft. per

Some water from the pulp drains.

4 minute or below are illustrated in Fig. 8. Thus a suction box 23 maybe provided inside the large diameter roller 17 since in this case thespeed of the travelling carrier band may not impart sufiicient momentumto the pulp to cause the water to flow up the surface of a waterway 19.Thus water is drawn through the upper wire into the suction box 23. Thebox may extend throughout a portion of the lower half of the roller 17and it may consist of a plurality of sections 29, 30, 31 operating underdifferent degrees ofvacuum, e.g. a higher degree of vacuum may bedesirable at the nip (section 31) than elsewhere, so that as formationprogresses, and hence water has to be drawn through already formedfibres, a greater degree of vacuum is exerted on the pond.

In another modification for a slow running machine (200 ft. perminute)see also Fig. 8-a suction box 32 is provided beyond the largediameter roller either in place ofor in addition to the waterway 19.This operates on the pulp after it has passed the nip. The said suctionbox 32 may be located before or beyond the waterway 19 when the twomechanisms are used together, and in an alternative a suction box may beused that comprises a waterway 33 at its rearward end. Thus said end issloped and is slotted a short distance up the slope so that waterflowing up the sloping face passes into or is drawn into the slot.

Instead of providing a plain slice such as 19, said slice may besuctionized.

Reference has hereinbefore been made to the roller 17 being ofcomparatively large diameter and it is to be understood that this meansthe dimensions of the roller are sufiicient to provide a reasonablesized forming area (tapering gap) for the turbulent pond commensuratewith the speed of the machine and nature and consistency of the pulp tobe dewatered. It should be mentioned that the nature and consistency ofthe pulp alters the characteristics of the turbulent pond. For exampleheavily beaten stock, which does not readily part with its water, mayprovide a higher and longer pond than pulps that part with their watereasily.

For example in a high speed machine where the pond is, say, two inchesin extent a roller of five inches diameter would probably sulfice. Whenhowever a machine is running slowly and the pond extends, say, for twofeet, then a roller up to three feet in diameter may be desirable. Itmight be assumed. that a two foot pond would require at least a fourfoot diameter roller, but this is not so because the height of the ponddoes not increase directly in proportion to its length. and so a goodportion of a four footroller would remain unused and clearly it is notdesirable to use. an unnecessarily large roller because of increaselcosts occasioned thereby.

It is of course desirable to provide aroller that is suitable for allspeeds of travel of carrier band and all consistencies and nature ofstock. so. that any individual machine may be readily adapted fordifferent conditions, and the most suitable dimensions for this purposeappears to be a roller of about 3 feet diameter.

In some instances it has been. found advantageous to provide an enclosedspace beyond the roller 17 extending up to the waterway 19 as'by thismeans the operation of suction can be more accurately controlled.

Although it is hereinbefore stated that the roller 17 squeezes the upperwire 10 and the carrier band together 6, it is to be understood thatthis may only be so when the machine is in operation. For example, if apulp containing 98% water and 2% solids has its water content reduced to96% when it reaches the nip and the layer consisting of 96% water is,say A" thick, then the roller 17 may beset so as to provide a' A gap.his thought that in practice the travelling carrier band gives under theinfluence of thepulp when the machine is inoperation.

I claim as my invention:

1. Apparatus for making fibrous webs from awatery pulp comprising, atraveling permeable carrier band having a horizontal upper run for thepulp, a looped upper forming wire having a horizontal lower run forcoaction with the said upper run, a permeable oncoming roller for theforming wire arranged to maintain the lower run thrusting against thecarrier band and to provide a wedgeshaped entry to the horizontal runs,said entry being defined by the periphery of the roller in cooperationwith the said upper run, means for delivering watery pulp to said entry,and an inclined waterway in the loop of the upper forming wiredownstream from the roller for receiving and removing water passing fromthe pulp through the periphery of the roller.

2. Apparatus for making fibrous webs from a watery pulp comprising, alooped traveling permeable carrier means having a first run for thepulp, a forming wire having a second run opposite to said first run, apermeable oncoming roller for the forming wire in the loop thereofpositioned to urge said second run firmly against said carrier means andto provide a wedge-shaped entry having an outlet of restricted depth tosaid opposite runs, said entry being defined by the periphery of saidroller in cooperation with said first run, means for delivering waterypulp to said entry, and means for receiving and removing water passingfrom the pulp through the periphery of the roller.

3. Apparatus for making fibrous webs from a watery pulp comprising, alooped traveling permeable carrier band having a first run for the pulp,means for delivering watery pulp to said carrier band, a looped formingwire having a second run parallel to said first run, an oncoming rollerfor said forming wire in the loop thereof, a sloping chute in the loopof the forming wire positioned across the upper surface of said secondrun of said forming wire beyond said roller, the surface of said rollercomprising a plurality of cells formed by transverse and peripheralstrips in said roller, said transverse strips being arranged at an angleto the radius of the roller to pick up water passing into said cellswhen the roller is rotated and to fling it towards said chute, saidroller being positioned to urge said second run firmly against saidcarrier means and to provide therewith a tapering gap that constitutes arestriction to the free flow of watery pulp along said carrier means sothat a turbulent pond of pulp is built up in said gap, water from saidpond flowing into said permeable cellular roller and being transmittedtherethrough to said chute.

4. Apparatus for making fibrous webs from a watery pulp comprising alooped travelling permeable carrier means having a first run for thepulp, an upper looped forming wire having a second run parallel to saidfirst run, an oncoming roller for the forming wire in the loop thereof,said roller being positioned to urge said second run firmly against saidcarrier means and to provide therewith a tapering gap that constitutes arestriction to the free flow of watery pulp along said carrier means sothat a turbulent pond of pulp is built up in said gap, a water removalchute in the loop of the forming wire downstream from the oncomingroller, a plurality of polygonal cells at the surface of said oncomingroller formed by transverse and peripheral strips of said surface, saidcells constituting means for receiving water from the pond at the gapand for flinging said water to said chute for upwards removal.

References Cited in the file of this patent UNITED STATES PATENTS811,660 Parker Feb. 6, 1906 2,141,393 Hutchins Dec. 27, 1938 2,730,933Reynolds Jan. 17, 1956 2,821,120 Thomas et al Jan. 28, 1958

